Method of heating of rolling mill rolls for the rolling of heated metal particles



. March 19, 1968 E. GEHRING ET AL 3,374,295

METHOD OF HEATING OF ROLLING MILL ROLLS FOR THE ROLLING OF HEATED METAL PARTICLES Filed Jan. 24, 1966 United States Patent Office 3,374,295 METHOD OF HEATING OF ROLLING MILL ROLLS FOR THE ROLLING OF HEATED METAL PARTICLES Eckard Gehring, Dusseldorf-Kaiserswerth, and Oswald Kaiser, Lintorf, near Dusseldorf, Germany, assignors to Schloemann Aktiengesellschaft, Dusseldorf, Germany Filed Jan. 24, 1966, Ser. No. 522,722 Claims priority, application Germany, Jan. 23, 1965, Sch 36,423 3 Claims. (Cl. 26352) ABSTRACT OF THE DISCLOSURE A method of rolling strips and sections from heated metal particles by so adjusting the roll gap that the heated metal particles can pass through in contact with the rolls but Without deformation, thereby heating the rolls, and then readjusting the roll gap and rolling the particles to the desired form and dimensions. The particles first passed through, being unchanged, may be immediately rolled in the second stage. Heated protective gas may be supplied to the furnace that heats the granules.

This invention relates to a method of heating the rolls of a rolling mill for the production of strips or sections in a plant consisting of a rolling mill preceded by a continuous heating or pusher-type furnace for the heating of metal particles. The heating of the rolls before the actual commencement of rolling is necessary in order that they may not be damaged by stress cracks, and thereby become useless, as a result of local heating in conjunction with the roll pressure. The heating of the rolls is usually effected in a known manner by means of gas-burners.

The object of the invention is to enable the heating of the rolls to be carried out without supplementary appliances which would not be required for the actual rolling process.

According to the invention this result is obtained by enlarging the roll gap, before the commencement of the rolling operation, by adjusting the rolls, to such an extent that the heated metal particles, passing from the furnace outlet into the roll gap and coming contact with the external surfaces of the rolls, pass through the roll gap without deformation. Owing to the fact that the particles themselves are employed for heating the rolls, supplementary devices designed for this purpose are not required. Since, moreover, before the commencement of rolling, constant temperature and passage conditions of the particles are expected at the outlet, the heat of the metal particles leaving the furnace during this time admits of being advantageously utilised.

In a further development of the invention, it is possible to use, in addition to the metal particles, for the heating of the rolls, the hot protective gas, under the atmosphere of which the particles of certain metals, such for instance as steel or copper, are supplied to the roll gap during the rolling operation. For this purpose again no supplementary devices are required, since the metal particles, from the furnace outlet to the roll gap, are in any case enclosed by a shaft which is filled with protective gas. This shaft accordingly forms at the same time the supply conduit for the protective gas for heating the rolls.

To enhance the action, metal particles and protective 3,374,295 Patented Mar. 19, 1968 gas may advantageously be supplied to the rolls at the same time to heat them.

An installation for producing strips or sections from metal particles, for which this method is intended, when heated in a continuous-heating or pusher-type furnace preceding the rolling mill, is illustrated in principle by the accompanying drawing.

In this drawing, 1 denotes a tubular furnace constructed as a continuous-heating or pusher-type furnace, which bears with its outer casing upon rollers 3 which can be driven, and revolves about its axis 4. Owing to the inclination of the furnace from the horizontal, the metal particles 5 travel from the furnace inlet 6 to the furnace outlet 7, where they fall into the roll gap 8 between a pair of rolls 9 of a rolling mill.

The metal particles 5 are supplied from a storage receptacle, constructed as a hopper 11, to a shaking conveyor channel 12, and from there to the furnace inlet 6. Between the furnace outlet 7 and the pair of rolls 9 is arranged a feed shaft 13 surrounding the stream of particles 5. In the neighbourhood of the mouth of the furnace the feed shaft is provided with a pipe connection 14, through which protective gas is supplied to the furnace and to the feed shaft in the direction of the arrow 15.

For the heating of the rolls 9 before the actual commencement of rolling, the rolls 9 are adjusted to such a distance apart that the remaining roll gap 8 just allows the current of particles 5 coming from the furnace outlet 7 to pass through without deformation. By the impact of the metal particles 5 upon the roll surfaces 16, and by their thermal radiation, they heat up the rolls 9, which are already revolving during this heating process. As soon as the metal particles 5 have left the rolls 9 they are brought by a delivery device 17 out of the neighbourhood of the rolls 9 and delivered into a collecting vessel 18 for example, which is installed beside the rolling mill. To enhance the delivery of heat, and thereby shorten the heating time for the pair of rolls, there may be supplied through the connection 14 additional protective gas, which flows through the feed shaft 13 to the roll gap 8, and thereupon escapes at that point into the open air.

As soon as the rolls 9 have been brought up to the required temperature, the roll gap is adjusted to correspond to the thickness of the desired strip or section, and now the actual rolling operation is started.

We claim:

1. A method of heating the rolls of a rolling mill for the production of strips or sections from metal particles, comprising: heating the metal particles in a downwardly inclined tubular furnace, admitting heated protective gas to the tubular furnace, adjusting the roll gap of the rolling mill to such a width that the heated particles can pass through it in contact with the roll surfaces without deformation, passing the heated particles, before the commencement of rolling, through the enlarged roll gap, with the rolls revolving, and at the same time causing a current of heated protective gas to impinge upon the roll surfaces.

2. A method of rolling strips and sections in a rolling mill from heated metal particles, comprising the steps of: adjusting the roll gap between the rolls to such a distance that the metal particles can pass through the roll gap without deformation, rotating the rolls while passing the heated particles through the roll gap and thereby heating the rolls, then readjusting the roll gap to the distance requisite for the deformation and consolidation of the particles, and finally passing the particles through the readjusted roll gap.

3. A method of rolling strips and sections in a rolling mill from heated metal particles, comprising the steps of: adjusting the roll gap between the rolls to such a distance that the metal particles can pass through the roll gap in contact with the rolls without deformation, heating the metal particles by passing them through a continuous heating furnace, supplying heated protective gas to the furnace, then readjusting the roll gap to the distance requisite for the deformation and consolidation of the particles, and

finally passing the particles through the readjusted roll gap. 10

References Cited UNITED STATES PATENTS 530,094 12/1884 Davis 72200 1,370,331 1/1901 McKibbin 72-200 2,933,305 4/1960 Reed et al 2662.5

FREDERICK L. MATTESQN, JR., Primary Examiner. JOHN J. CAMBY, Examiner. 

